Powder metallurgical processing of Ni–Ti–Zr alloys undergoing martensitic transformation—part II

Monastyrsky, G.E.; Humbeeck, Jan Van; Kolomytsev, V. I.; Yu, Nian

doi:10.1016/s0966-9795(02)00039-0

Cited by 14 publications

(5 citation statements)

References 26 publications

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“…It can be seen from Figure 7a that the Ti-30Zr-5Ni alloy is composed of dual phases, in contrast with the single-phase structures of the abovementioned ternary Ti-Zr based alloys, and the volume ratio of the second phase increases with increasing Ni content, as shown in Figure 7b. The XRD result in Figure 7c indicates that the dual phases can be confirmed as the α -martensite phase and the second phase as (Ti,Zr) 2 Ni, which has already been found in Ni-Ti-Zr alloys [24]. This result suggests that Ni is also an α-stabilizer or a moderate element and the solid solubility of Ni in Ti-Zr alloy is no more than 5%.…”

Section: Resultssupporting

confidence: 55%

Phase stability and hardness of some ternary Ti–Zr based shape memory alloys

Zhifang

Cui

et al. 2011

International Journal of Smart and Nano Materials

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The phase stability and hardness of Ti-30Zr-M (M = Nb, V, Cr, Mo, Fe, Ni and Al) shape memory alloys were investigated by structural observations, d-electron alloy design and microhardness tests. Optical microscopy and X-ray diffraction results show that Nb, V, Cr, Mo and Fe are all β-stability elements in Ti-30Zr-M alloys with the effect enhanced by the presence of Zr. The composition of the least stable β-phase alloy values of Nb, V, Cr, Mo and Fe in Ti-30Zr alloys are 12%, 9%, 5%, 3% and 2%, respectively, indicating an increasing sequence of the β-stability ability. Ni and Al show α-stability or moderate effects and the addition of Ni induces the appearance of (Ti, Zr) 2 Ni phase in Ti-30Zr-5/15Ni alloys. Based on the d-electron alloy design method, the bond order of Ti and alloying atoms (Bo) and the metal d-orbital energy level (Md) are calculated to build the Bo-Md diagram of Ti-30Zr-M alloys associated with the phase structure identification. The microhardness of Ti-30Zr alloy is increased by addition of a small amount of the alloying element, except for Nb. There is a drop of the microhardness of each Ti-30Zr-M alloys when β phase appears by the addition of more alloying elements.

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Section: Resultssupporting

confidence: 55%

Phase stability and hardness of some ternary Ti–Zr based shape memory alloys

Zhifang

Cui

et al. 2011

International Journal of Smart and Nano Materials

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“…Therefore, the application of powder metallurgy (P/M) process that is a solid-state process has been tried to fabricate Ti-Ni-Zr SMA. Monastyrsky et al 2,3) reported that the P/M processed Ti-Ni-Zr alloys have many types of secondary phases such as Ti-Ni alloy (Ti 2 Ni, TiNi 3 ) and Ni-Zr alloy (NiZr 2 , Ni 5 Zr). Bertheville 4) reported that almost singlephase ternary Ti-Ni-Zr alloys can be obtained using finer TiH 2 and ZrH 2 powders, although a few Zr-rich secondary phases exist in the alloy.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Ti-Ni-Zr Shape Memory Alloy by P/M Process

Terayama¹,

Nagai

Kyogoku

2009

Mater. Trans.

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This work focuses on the fabrication of Ti-Ni-Zr high-temperature shape memory alloy by powder metallurgy (P/M) process. The effects of fabrication conditions on the microstructure and shape memory characteristics of Ti-50.2 mol%Ni-5 mol%Zr alloy were investigated. In this research, elemental Ti, Ni and Zr powders were used. These powders were mixed by a planetary ball mill at a rotational speed of 500 rpm for milling times of 0.6 ks (mixed powder) and 720 ks (MAed powder). The mixtures were sintered by a pulse-current pressure sintering equipment at 1153 K for sintering times of 1.8 ks and 1.2 ks. The solution treatment was carried out at various temperatures between 1073 K and 1273 K to homogenize the microstructure of the as-sintered alloy. The microstructure of the alloy became more homogeneous with an increase in solutiontreatment temperature. In the case of the mixed powder, however, Zr-rich phases were observed in the microstructure of the solution-treated alloy. The alloy solution-treated at 1173 K showed a yielding behavior in the stress-strain curve, and the tensile strength and elongation of the alloy were more than 350 MPa and 2.5%, respectively. On the other hand, in the case of the MAed powder, the microstructure of the as-sintered alloy was homogeneous. The P/M alloy showed higher transformation temperatures than those of the wrought alloy. But, the alloy showed no shape memory effect and poor tensile property due to contamination of the MAed powder.

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“…Solid processing using P/M has also been applied to synthesize both conventional [103,104,105,106,107,108] and ferromagnetic shape memory materials [66,67,68,69,70,71], although its application has been widespread in the former category. Apart from the application of P/M in conventional shape memory materials, its observed benefits have been the ability to obtain the desired martensitic transformation temperatures, transformation width (range) and hysteresis, as in Cu-Al-Ni [109], drop in transformation temperatures, as in Ti-Ni-Cu [110] and, more importantly, significant reduction in the number of secondary phases using vapor phase calciothermic reduction (VPCR) in solid-state sintering of Ni 50 Ti 50−x Zr x [111].…”

Section: Methods Of Synthesis and Characterizationmentioning

confidence: 99%

Ferromagnetic Shape Memory Heusler Materials: Synthesis, Microstructure Characterization and Magnetostructural Properties

et al. 2018

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An overview of the processing, characterization and magnetostructural properties of ferromagnetic NiMnX (X = group IIIA–VA elements) Heusler alloys is presented. This type of alloy is multiferroic—exhibits more than one ferroic property—and is hence multifunctional. Examples of how different synthesis procedures influence the magnetostructural characteristics of these alloys are shown. Significant microstructural factors, such as the crystal structure, atomic ordering, volume of unit cell, grain size and others, which have a bearing on the properties, have been reviewed. An overriding factor is the composition which, through its tuning, affects the martensitic and magnetic transitions, the transformation temperatures, microstructures and, consequently, the magnetostructural effects.

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Powder metallurgical processing of Ni–Ti–Zr alloys undergoing martensitic transformation—part II

Cited by 14 publications

References 26 publications

Phase stability and hardness of some ternary Ti–Zr based shape memory alloys

Phase stability and hardness of some ternary Ti–Zr based shape memory alloys

Fabrication of Ti-Ni-Zr Shape Memory Alloy by P/M Process

Ferromagnetic Shape Memory Heusler Materials: Synthesis, Microstructure Characterization and Magnetostructural Properties

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